Question

The energy of decomposition of X is 5 eV/molecule. Which of the following wavelength can be used for the decomposition?

Answer 1

Given : The energy of decomposition of X is 5 eV/molecule.

To find : The wavelength can be used for the decomposition.

solution : using formula, E = hc/λ

where h is plank's constant i.e., h = 6.63 × 10¯³⁴ Js , c is the speed of light in vacuum i.e., c = 3 × 10^8 m/s and λ is wavelength.

here, E = 5 eV/molecule

= 5 × 1.6 × 10^-19 J

= 8 × 10^-19 J

now, 8 × 10^-19 = (6.63 × 10¯³⁴ × 3 × 10^8)/λ

⇒λ = (19.89 × 10¯²⁶)/(8 × 10^-19)

⇒λ = 2.48625 × 10^-7 m = 248.625 nm

Therefore the wavelength can be used for the decomposition would be 248.625 nm